Noninvasive apparatus for ablating turbinates

ABSTRACT

An apparatus is provided for ablating at least a portion of a nasal concha. By ablating at least a portion of a nasal concha, the size of the nasal concha is reduced. The three nasal concha in the body (inferior, middle and superior nasal concha) form at least a portion of the three nasal meatus (inferior, middle and superior nasal meatus) in the body. By reducing the size of a nasal concha, obstruction of a nasal meatus is reduced or eliminated. As a result, air flow through the nasal meatus is improved. In one embodiment, the apparatus includes a catheter having a distal portion with a dimension configured for positioning the catheter distal portion through a nostril of a patient into a nasal meatus adjacent a surface of a nasal concha and a means at the catheter distal portion for delivering sufficient ablative energy to the nasal concha to ablate at least a portion of the nasal concha through heating without penetrating the surface of the nasal concha with an element of the apparatus.

RELATIONSHIP TO COPENDING APPLICATIONS

This application is a continuation-in-part of application Ser. No.08/754,588, "Method for Ablating Turbinates", filed Nov. 19, 1996 andapplication Ser. No. 08/753,063, "Apparatus for Ablating Turbinates",filed Nov. 19, 1996 both of which are a continuation-in-part ofapplication Ser. No. 08/651,796, "Method and Apparatus for AblatingTurbinates" filed May 22, 1996, now abandoned, and of application Ser.No. 08/651,798, "Method and Apparatus for Ablating Turbinates", filedMay 22, 1996 (now abandoned); all of which are a continuation-in-part ofapplication Ser. No. 08/265,459, "Thin Layer Ablation Apparatus", filedJun. 24, 1994, now U.S. Pat. No. 5,505,730, all of which areincorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a method and apparatus for treatingairway obstructions. More specifically, the present invention relates toa method and apparatus for reducing the volume of the turbinates inorder reduce nasal airway obstructions.

BACKGROUND OF THE INVENTION

Sleep-apnea syndrome is a medical condition characterized by daytimehypersomnomulence, morning arm aches, intellectual deterioration,cardiac arrhythmias, snoring and thrashing during sleep. It is caused byfrequent episodes of apnea during the patient's sleep. The syndrome isclassically subdivided into two types. One type, termed "central sleepapnea syndrome", is characterized by repeated loss of respiratoryeffort. The second type, termed obstructive sleep apnea syndrome, ischaracterized by repeated apneic episodes during sleep resulting fromobstruction of the patients upper airway or that portion of thepatient's respiratory tract which is cephalad to, and does not include,the larynx.

Treatment for sleep apnea includes various medical, surgical andphysical measures to unobstruct the airways. Medical measures includethe use of medications such as protriptyline, medroxyprogesterone,acetazolamide, theophylline, nicotine and other medications in additionto avoidance of central nervous system depressants such as sedatives oralcohol. The medical measures above are sometimes helpful but are rarelycompletely effective. Further, the medications frequently haveundesirable side effects.

Surgical interventions have included uvulopalatopharyngoplasty,tonsillectomy, surgery to correct severe retrognathia and tracheostomy.Other surgical procedures include pulling the tongue as forward aspossible and surgically cutting and removing sections of the tongue andother structures which can close off the upper airway passage. Theseprocedures may be effective but the risk of surgery in these patientscan be prohibitive and the procedures are often unacceptable to thepatients.

Among the air passageways in the body that can become obstructed are thenasal passageways leading from the nose to the pharynx. There are threenasal passageways, namely the inferior, middle and superior nasalmeatus. The turbinates, also referred to as nasal concha, are a seriesof tissues which form at least a portion of these nasal passageways.Forming a portion of the inferior nasal meatus is the inferior nasalconcha. The inferior and middle nasal concha each form a portion of themiddle nasal meatus. The middle and superior nasal concha each form aportion of the superior nasal meatus. When the inferior, middle and/orsuperior nasal concha become enlarged, the various nasal meatus whichallow air to pass through the nose into the pharynx can becomeobstructed.

Opening of obstructed nasal airways by reducing the size of theturbinates has been performed using surgical and pharmaceuticaltreatments. Examples of surgical procedures include anterior andposterior ethmoidectomy, such as those described in "EndoscopicParanasal Sinus Surgery" by D. Rice and S. Schaefer, Raven Press, 1988);the writings of M. E. Wigand, Messerklinger and Stamberger; and U.S.Pat. No. 5,094,233. For example, as described in U.S. Pat. No.5,094,233, the Wigand procedure involves the transection of the middleturbinate, beginning with the posterior aspect, visualization of thesphenoid ostium and opening of the posterior ethmoid cells forsubsequent surgery. In the sphenoidectomy step, the ostium of thesphenoid is identified and the anterior wall of the sinus removed.Following this step, the posterior ethmoid cells may be entered at theirjunction with the sphenoid and the fovea ethmoidalis can be identifiedas an anatomical landmark for further dissection. In anteriorethmoidectomy, the exenteration of the ethmoids is carried anteriorly tothe frontal recess. Complications, such as hemorrhage, infection,perforation of the fovea ethmoidalis or lamina papyracea, and scarringor adhesion of the middle turbinate, are reported in connection withthese procedures.

A particular problem encountered has been postoperative adhesionoccurring between the turbinates and adjacent nasal areas, such asmedial adhesion to the septum and lateral adhesion to the lateral nasalwall in the area of the ethmoid sinuses. Otherwise successful surgicalprocedures may have poor results in these cases. Some surgeons haveproposed amputation of a portion of the turbinate at the conclusion ofsurgery to avoid this complication, resulting in protracted morbidity(crust formation and nasal hygiene problems). The turbinate adhesionproblem detracts from these endoscopic surgical procedures. Efforts havebeen made to reduce the complications associated with the surgicaltreatment of turbinate tissue, for example by the use of a turbinatesheath device. U.S. Pat. No. 5,094,233.

U.S. Pat. No. 3,901,241 teaches a cryosurgical instrument which is saidto be useful for shrinking nasal turbinates. U.S. Pat. No. 3,901,241.

Pharmaceuticals have also been developed for reducing the size of theturbinates. However, pharmaceuticals are not always completelyefficacious and generally do not provide a permanent reduction inturbinate size. In addition, pharmaceuticals can have adverse sideeffects.

A need exists for a method and device for clearing obstructed nasalpassageways. It is preferred that the method and device be performablewith minimal surgical intervention or post operative complications. Itis also preferred that the method and device be performable so as toreduce the size of the turbinates without the surgical cutting orremoval of tissue. It is also preferred that the method and deviceprovide a permanent reduction in turbinate size.

SUMMARY OF THE INVENTION

An apparatus is provided for ablating at least a portion of a nasalconcha. The apparatus includes a catheter having a distal portion with adimension configured for positioning the catheter distal portion througha nostril of a patient into a nasal meatus adjacent a surface of a nasalconcha, and a means at the catheter distal portion for deliveringsufficient ablative energy to the nasal concha to ablate at least aportion of the nasal concha through heating. According to thisinvention, the apparatus ablates the nasal concha without penetratingthe surface of the nasal concha with an element of the apparatus.

In one embodiment, the apparatus includes an insulating means forpreventing the delivery of ablative energy to a selected tissue sectionforming a portion of the nasal meatus. The insulating means may also bedesigned to prevent the delivery of ablative energy to a selectedportion of the nasal concha.

The energy delivery means can be designed to deliver several differentforms of energy. Examples of these energy forms include, but are notlimited to RF, microwave, ultrasound, pulsed laser, and diffused laserenergy. In a preferred embodiment, the energy delivery means deliverselectromagnetic energy and more preferably RF energy.

In one embodiment, the energy delivery means delivers ablative energythrough the surface of the nasal concha into an interior section of thenasal concha. In another embodiment, the energy delivery means deliversablative energy through the surface of the nasal concha into an interiorsection of the nasal concha substantially bloodlessly. The energydelivery means may also be used to deliver ablative energy through thesurface of the nasal concha into an interior section of the nasal conchawithout the formation of an external wound on the surface of the nasalconcha.

An apparatus is also provided for ablating an interior portion of anasal concha without ablating tissue forming a surface of the nasalconcha. In one embodiment, the apparatus includes a catheter having adistal portion with a dimension configured for positioning the catheterdistal portion through a nostril of a patient into a nasal meatusadjacent a surface of a nasal concha, and a means at the catheter distalportion for delivering sufficient ablative energy to the internalsection of the nasal concha to ablate the internal section throughheating without ablating tissue at the surface of the nasal concha.

The energy delivery means used in this apparatus can be designed todeliver several different forms of energy. Examples of these energyforms include, but are not limited to RF, microwave, and ultrasound. Ingeneral, any form of energy may be used which is capable of penetratingtissue and causing localized heating of the tissue. In a preferredembodiment, the energy delivery means delivers electromagnetic energyand more preferably RF energy.

In one embodiment, the energy delivery means delivers ablative energy tothe internal section of the nasal concha without penetrating the surfaceof the nasal concha with an element of the apparatus. The energydelivery means may also be designed to deliver ablative energy to theinternal section of the nasal concha without the formation of a wound onthe surface of the nasal concha.

In one embodiment, the apparatus further includes a cooling means forcooling the surface of the nasal concha during the delivery of ablativeenergy. In one variation of this embodiment, the cooling means isadapted to receive a cool medium from a medium source which cools thesurface of the nasal concha.

The apparatus may also include an expandable member which conforms tothe surface of the nasal concha when expanded. In one embodiment, thecooling means is coupled to the expandable member for cooling thesurface of the nasal concha during the delivery of ablative energy. Forexample, the expandable member may be adapted to receive a cool mediumfrom a medium source to cool the surface of the nasal concha.

The apparatus may optionally include an insulating means for preventingthe delivery of ablative energy to a selected tissue section forming aportion of the nasal meatus. The insulating means may also be designedto prevent the delivery of ablative energy to a selected portion of thenasal concha.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates the construction of the nasal passageways of thehuman nose.

FIG. 2 illustrates the effect enlargement of a nasal concha has on anasal air passageways.

FIGS. 3A-3C illustrate an embodiment of a method for ablating a nasalconcha.

FIG. 3A illustrates the introduction of an apparatus through a nostrilinto a nasal meatus adjacent a surface of a nasal concha.

FIG. 3B illustrates the expansion of the expandable member within thenasal meatus so that the energy delivery device is brought into energycommunication with the surface of the nasal concha to be treated.

FIG. 3C illustrates the delivery of energy to a selected portion of anasal concha by selecting the placement of the apparatus within thenasal meatus.

FIG. 3D illustrates insulating at least a portion of the nasal conchafrom ablative energy.

FIGS. 4A-C illustrate the steps of ablating a portion of a nasal conchaaccording to the present invention.

FIG. 4A illustrates the step of introducing ablative energy into aninterior section of a nasal concha.

FIG. 4B illustrates an ablated tissue region and its absorption by thebody.

FIG. 4C illustrates the resulting reduction in the size of the nasalconcha.

FIG. 5 illustrates an apparatus according to the present invention.

FIG. 6 illustrates the use of a plurality of ring electrodes in anapparatus according to the present invention.

FIG. 7 illustrates an apparatus which includes an insulator forselectively delivering ablative energy to a desired section of a nasalconcha.

FIG. 8 is a block diagram of a feedback control system useful with themethod and apparatus of the present invention.

FIG. 9 is a block diagram illustrating an analog amplifier, analogmultiplexer and microprocessor used with the feedback control system ofFIG. 8.

FIG. 10 is a block diagram of a temperature/impedance feedback systemthat can be used to control cooling medium flow rate through anapparatus of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention provides a method and apparatus for ablating atleast a portion of a nasal concha (turbinate). By ablating at least aportion of a nasal concha, the size of the nasal concha can be reduced.Accordingly, the present invention also provides a method for reducingthe size of a nasal concha. The three nasal concha in the body(inferior, middle and superior nasal concha) form at least a portion ofthree nasal meatus (inferior, middle and superior nasal meatus) in thebody. By reducing the size of a nasal concha, obstruction of a nasalmeatus can be reduced. By reducing an obstruction of a nasal meatus, airflow through the nasal meatus is improved. Accordingly, the presentinvention also relates to a method for improving airflow through a nasalmeatus of the body.

FIG. 1 illustrates the construction of the nasal passageways of thehuman nose 100. As illustrated in the figure, the human nose includes anostril 102 which leads into the nasal passageways from outside the bodyand a nasopharyngeal opening 104 which leads into the nasal passagewaysfrom the pharynx 106. Connecting the nostril 102 and nasopharyngealopening 104 are a series of passageways, namely the inferior nasalmeatus 108, the middle nasal meatus 110, and the superior nasal meatus112. Forming at least a portion of each of these passageways are thenasal concha, also referred to as the turbinates. Forming at least aportion of the inferior nasal meatus 108 is the inferior nasal concha114. Forming at least a portion of the middle nasal meatus 110 is theinferior nasal concha 114 and the middle nasal concha 116. Forming atleast a portion of the superior nasal meatus 112 is the middle nasalconcha 116 and the superior nasal concha 118. As also shown in FIG. 1,the inferior nasal concha 114 includes an anterior portion 120 whichterminates adjacent the nasopharyngeal opening 104 and a posteriorportion 122 which terminates adjacent the nostril 102.

Ablation of a nasal concha is accomplished according to the presentinvention by the introduction of ablative energy into a section of nasalconcha tissue. The use of ablative energy eliminates the need forsurgical cutting to remove a portion of a nasal concha and the risksassociated therewith. As a result, the procedure can be performedbloodlessly and without the need to penetrate tissue, therebysignificantly reducing the risk of infection. By cooling the surface ofthe nasal concha being ablated, ablation can be performed to remove aninternal section of a nasal concha without damaging the surface of thenasal concha. As a result, the present invention provides a method forreducing the size of a nasal concha without the formation of a wound onthe surface of the nasal concha. This approach should be significantlyless painful for the patient than traditional surgical methods.

According to the present invention, it is preferred to ablate theinferior nasal concha 114, and more preferably an anterior portion 120of the inferior nasal concha 114. In a preferred embodiment, theanterior portion 120 of the inferior nasal concha 114 is defined asbeing no larger than about one-third the volume of the inferior nasalconcha 114. Thus, in one embodiment, the method includes ablating nomore than about one-third of the inferior nasal concha 114.

FIG. 2 illustrates the effect enlargement of a nasal concha has on anasal air passageways. As shown in FIG. 2, enlargement of the inferiornasal concha 114 can result in an obstruction of inferior nasal meatus108. By reducing the size of the inferior nasal concha 114, illustratedin FIG. 2 by region below dashed line 123, the inferior nasal meatus 108is reopened.

1. Method For Turbinate Ablation

One aspect of the present invention relates to a method for ablatingnasal concha tissue. FIGS. 3A-3D illustrate an embodiment of thismethod. As shown in FIG. 3A, an apparatus 124 having a distal portion128 with an expandable member 132 and an energy delivery device 134 fordelivering ablative energy is introduced through a nostril 102 into anasal meatus adjacent a surface of a nasal concha, shown in the figureas the inferior nasal meatus 108 and the inferior nasal concha 114.

As shown in FIG. 3B, the expandable member 132 is expanded within thenasal meatus 108 so that the expandable member 132 is brought intocontact with the surface 115 of the nasal concha 114 to be treated.Ablative energy 117 is then delivered through the apparatus and theenergy delivery device 134 to the nasal concha 114. Sufficient energy117 is delivered through the surface 115 of the nasal concha 114 toablate at least a portion 119 of the nasal concha 114.

According to this method, the ablative energy may be any form of energycapable of causing the ablation of tissue by heating at least a portionof the nasal concha being treated to a temperature above about 40° C.Examples of types of energy that may be used include, but are notlimited to energy from a diode laser ablation, a laser fiber (defused),microwave (915 MHz and 2.45 GHz), ultrasound, and RF at all relevantfrequencies. In a preferred embodiment, the energy is electromagneticenergy and is preferably RF radiation or microwave radiation.

When the energy is RF radiation, the energy preferably has a frequencybetween about 300 megahertz and about 700 megahertz. The RF energydelivered to the nasal concha is preferably sufficient to deliverbetween about 5 and about 30 watts of RF energy to at least a portion ofthe nasal concha being treated.

According to this method, the expandable member is preferably expandedby delivering a medium into the expandable member. FIG. 3C illustratesthe delivery of the medium 138 through a lumen 135 within the distalportion of the apparatus into the expandable member 132 to expand theexpandable member 132. The electrolytic medium 138 exits the lumen 135through apertures 137 in the lumen wall. Accordingly, a further step ofthe method includes expanding the expandable member by delivering amedium into the member.

The medium may be any media capable of conducting energy from the energydelivery device to the nasal concha to be ablated. The medium can be afluid or a gel. When RF energy is used, the medium is preferably adielectric substance, such as saline, which aids the delivery of energy,referred to herein as an electrolytic medium. In one particularembodiment, the electrolytic medium is saline formed from distilledwater with a NaCl content of less than about 10% by weight. The mediumcan also include a variety of substances known in the art for providinga bioactive, chemoactive, or radioactive effect desirable in conjunctionwith the ablation of turbinates. Examples of such substances includeablative acidic or alkaline substances, antibiotics, chemotherapeuticagents, a fluorescent or radioactive dye or marker, or some combinationthereof.

In one embodiment of the method, the surface of the nasal concha to beablated is cooled during the delivery of energy to ablate the nasalconcha. The extent of cooling provided is preferably sufficient toprevent the nasal concha surface from being ablated. As a result, aninterior portion of a nasal concha is ablated without ablating thesurface of the nasal concha. In this regard, it is preferred that thecooling be sufficient to prevent the surface tissue from exceeding atemperature of about 40° C. In this embodiment, the energy used is of atype which can penetrate into an internal section of tissue despitesurface cooling. Examples of this type of energy include electromagneticenergy and ultrasonic energy.

Cooling serves at least two purposes. Cooling may be used to preventablation of the surface of the nasal concha by preventing the ablationof the surface of the nasal concha. As a result, an exposed wound siteis not generated during the method. Cooling may also be used to controlthe location of the ablation site. For example, cooling the nasal conchasurface enables the formation of an entirely internal ablation site. Theextent of cooling can be used to control the thickness of thenon-ablated tissue at the surface of the nasal concha adjacent theinternal ablation site.

Cooling may be accomplished, for example, by introducing cooled mediuminto the expandable member. Accordingly, the method may further includethe step of introducing cooled medium into the expandable member duringablation.

The nasal meatus into which the apparatus is delivered may be theinferior, middle and/or superior nasal meatus and is preferably theinferior nasal meatus. The nasal concha ablated may be the inferior,middle and/or superior nasal concha and is preferably the inferior nasalconcha. In one embodiment, energy is delivered to a selected section ofone of the nasal concha. For example, energy may be selectivelydelivered to the anterior or posterior sections of the inferior nasalconcha. Delivery of energy to a selected section of a nasal concha maybe accomplished by the placement of the apparatus within the nasalmeatus. The delivery of energy to a selected section of a nasal conchamay also be accomplished by insulating at least a portion of the nasalconcha from ablative energy.

As illustrated in FIG. 3D, an insulative covering 142 may be positionedover a portion of the expandable member 132 to control the delivery ofenergy to a selected section of tissue. Accordingly, a further step ofthe method includes delivering energy to at least a portion of a nasalconcha while insulating at least a portion of the tissue forming thenasal meatus from the energy being delivered to the nasal concha.

The present invention also relates to a method for reducing the size ofa nasal concha. According to the method, the size of a nasal concha isreduced by ablating tissue forming a nasal concha and removing theablated nasal concha tissue. Removal of the ablated nasal concha tissueis preferably accomplished by the natural absorption of ablated tissueby the patient's body.

FIGS. 4A-C illustrate the removal of an internal region of tissue byablation. FIG. 4A illustrates introducing ablative energy 144 into aninterior section of a nasal concha through the surface of the nasalconcha. Cooling of the surface of the nasal concha may be performed inorder to prevent the ablation of the surface of the nasal concha.

FIG. 4B illustrates the absorption (illustrated by arrows 148) of anablated tissue region 146 by the body. As illustrated in FIG. 4B, theablated tissue region 146 is an interior region, i.e., the surface 115of the nasal concha has not been ablated. This may be achieved bycooling the surface 115 of the nasal concha during the delivery ofablative energy to the nasal concha.

FIG. 4C illustrates the resulting reduction in the size of the nasalconcha after absorption. Region 149 illustrates the volume of tissuethat is removed from the path of the nasal meatus by this method. As canbe seen by comparing FIGS. 4A and 4C, the size of nasal meatus 108 isenlarged by this process.

The present invention also relates to a method for improving airflowthrough a nasal meatus by reducing the size of a nasal concha whichdefines at least a portion of the nasal meatus. This method can beaccomplished by the method for reducing the size of a nasal concha asdescribed above. In one embodiment, the rate of airflow through thenasal meatus at a given pressure is increased by at least 25%.

2. Turbinate Ablation Apparatus

The present invention also relates to an apparatus for ablating a nasalconcha. As illustrated in FIG. 5, the apparatus 124 includes a catheterbody 126 which has a distal portion 128 with dimensions configured forintroduction through a nostril of a patient into a nasal meatus of apatient.

An expandable member 132 is attached to the catheter body 126 at thecatheter distal portion 128. Also attached to the catheter body 126 atthe catheter distal portion 128 is an energy delivery device 134 fordelivering ablative energy.

According to the present invention, the expandable member preferablyconforms to the surface of the nasal concha to be ablated when theexpandable member is expanded. A variety of mechanisms known in the artmay be used to expand the expandable member. One mechanism, illustratedin FIG. 5, involves the use of a lumen 136 coupled with the catheterbody 126 for delivering a medium 138 to expand the expandable member132. The medium is delivered from a media source 159 through the lumen136 to within the expandable member 132 through apertures 137. Theapertures 137 may be formed by a sheath 150 which substantiallysurrounds the lumen 136. In one embodiment, the sheath 150 is formed ofa relatively inert and relatively hard substance, such as metalliccopper or metallic silver. In alternative embodiments, the sheath 150includes some other inert substance, such as gold, stainless steel,titanium, various plastic compounds, or some combination thereof.

The sheath preferably has a traverse diameter of about 6 french. (about0.090 inches). However, it should be understood that the sheath may havea variety of thicknesses. The sheath 150 also preferably has a thicknessof about 0.001 inches. This embodiment is particularly preferred in thecase when the sheath is copper.

The medium used to expand the expandable member is preferably anelectrolytic medium, i.e., a medium which is capable of conductingelectromagnetic energy and can be used to convey energy from the energydelivery device to the nasal concha to be ablated.

The expandable member is preferably formed of a material which ispermeable to the electrolytic medium used to expand the member. Byselecting the material used to form the expandable member such that itis permeable to the electrolytic medium, the electrolytic medium is ableto pass through the expandable member to the surface of the nasal conchabeing ablated during operation of the apparatus. In one embodiment, theexpandable member is an expandable porous membrane.

As illustrated in FIG. 5, the energy delivery device 134 may bepositioned within the expandable member. This energy delivery device maybe a needle electrode or a conductive film lining the outside of thelumen. The sheath may also serve as the energy delivery device.Alternatively, the energy delivery device may be positioned on a surface147 of the expandable member. The energy delivery device may be a singleenergy delivery device or may include a plurality of energy deliverydevices where energy is independently deliverable to each energydelivery device.

In one embodiment, illustrated in FIG. 6, the energy delivery deviceincludes one or more ring electrodes 156 disposed on the surface of theexpandable member 132. As illustrated, the plurality of ring electrodes156 may be disposed in parallel with their axes aligned with a long axis160 of the catheter body 126. As noted above, energy may be delivered toall of the energy delivery devices or may be independently delivered toeach energy delivery device.

In another embodiment, a plurality of energy delivery devices arepositioned on a surface of the expandable member. An example of asuitable surface for disposition on the membrane is described inapplication Ser. No. 08/319,373, "Thin Layer Ablation Apparatus", filedOct. 6, 1994, which is incorporated by reference. It is noted that acombination of ring electrodes and surface energy delivery devices maybe used.

In a further embodiment of the invention, illustrated in FIG. 7, theapparatus includes an insulator 162 which prevents the delivery ofablative energy 117 through at least a portion of the expandable member.As illustrated in FIG. 7, the insulator 162 may be positioned over thesurface 147 of the expandable member 132. Using the insulator 162,ablative energy can be delivered to a selected section of a nasal concha153 while preventing the ablation of another selected section of tissue155. For example, ablative energy can be selectively delivered to anasal concha forming at least a portion of the nasal meatus. Meanwhile,the insulator can be used to prevent the ablation of other portions ofthe nasal meatus.

As illustrated in FIG. 5, ablative energy is supplied to the energydelivery device by an energy source 162. As discussed above, a varietyof forms of ablative energy may be used in the present invention.Accordingly, the energy source is selected to provide the desired formof energy. The energy used is preferably RF energy which ablates theturbinate by heat and cell destruction.

In one embodiment, the energy source 162 includes an energy source 163(or a power regulator coupled to a standard energy source such as a wallsocket or battery), a signal generator 165 (such as a generator forpulses, sine waves, square waves, or some combination of these waveforms with each other or with some other wave form), and a processor 167for controlling the signal generator.

In a preferred embodiment, the signal generator generates pulses of RFenergy having an RF radiation frequency between about 300 megahertz andabout 700 megahertz, such as preferably about 465 megahertz. Inalternative embodiments, the RF energy may have an RF radiationfrequency in the microwave range or in another range of theelectromagnetic spectrum.

The processor controls the amount of energy delivered by the apparatus.In this embodiment, the apparatus can further include a signal generatorcoupled to the energy delivery device and coupled to a energy source.The apparatus can also include a processor coupled to the signalgenerator and disposed for controlling the signal generator. Accordingto this embodiment, the processor can control the way in which energy isdelivered. For example, the signal generator can generate pulses of RFenergy which provide between about 5 and about 30 watts of RF energy toat least a portion of the turbinate. The processor can also control theamount of energy produced so that the region of turbinate tissue to beablated is heated to a temperature of at least 40° C.

In order to monitor the amount of energy delivered and the amount ofheat generated, the apparatus can also include one or more sensors.These sensors can be used to detect a variety of operating parametersincluding the amount of energy delivered, the impedance generated, andthe temperature of a region adjacent the apparatus. These sensors canalso be used to provide feedback for controlling the operation of anenergy source which delivers energy to the energy delivery device. Inaddition, chemical or biochemical sensors can be used to detectablation.

In one embodiment, the apparatus includes at least one temperaturesensor, such as a thermocouple or thermistor. The temperature sensor iscoupled to a communication link (such as a conductor), which is coupledto the processor. For example, in the case where the temperature sensoris a thermocouple, the communication link may comprise a D/A convertercoupled to a register disposed for reading by the processor. Theprocessor reads an sensor value from the sensor and, responsive thereto,controls the signal generator so as to achieve delivery of an effectiveamount of RF energy to a desired section of tissue to be ablated. Theprocessor thus uses the signal generator, catheter distal portion,energy delivery device, and temperature sensor, as a feedback loop forcontrolled delivery of RF energy to a section of a nasal concha. Forexample, the processor may control the delivery of RF energy to achievedelivery of a selected amount of energy, to achieve a selectedtemperature, or to achieve a selected amount of ablation of a section ofa nasal concha. A variety of positionings for the sensors are possible.In one embodiment, the sensor is coupled to the expandable member.

As described above, the temperature or some other property of the tissuebeing ablated, or of the energy delivery device can be monitored using avariety of sensors. Illustrated in FIGS. 8 and 9 is an open and a closedloop feedback system for coupling a sensor used in the apparatus to anenergy source so that the output energy of the energy source is adjustedin relation to the property sensed by the sensor. The feedback system,is described herein with regard to the delivery of RF energy. It shouldbe noted, however, that the feedback system can be readily adjusted foruse with a variety of other types of energy, such as microwaves.

Using the feedback system, the physician can, if desired, override theclosed or open loop system. A microprocessor can be included andincorporated in the closed or open loop system to switch energy on andoff, as well as modulate the energy. The closed loop system utilizes amicroprocessor to serve as a controller, watch the temperature, adjustthe amount of energy being delivered, look at the result, re-feed theresult, and then modulate the energy.

In the case of RF energy, the sensors and feedback control system can beused to, maintained tissue adjacent to an energy delivery device at adesired temperature for a selected period of time without impeding out.An output maintains the energy delivered to the energy delivery devicefor a selected length of time.

As illustrated in FIG. 8, current is delivered through energy deliverydevice 189 is measured by current sensor 190. Voltage is measured byvoltage sensor 192. Impedance and energy are then calculated at energyand impedance calculation device 194. These values can then be displayedat a user interface and display 196. Signals representative of energyand impedance values are received by a controller 198.

A control signal is generated by controller 198 that is proportional tothe difference between an actual measured value, and a desired value.The control signal is used by energy circuits 200 to adjust the energyoutput in an appropriate amount in order to maintain the desired energydelivered at each energy delivery device 189.

In a similar manner, temperatures detected at temperature sensors 191provide feedback for maintaining a selected energy. The actualtemperatures are measured at temperature measurement device 202, and thetemperatures are displayed at user interface and display 196. A controlsignal is generated by controller 198 that is proportional to thedifference between an actual measured temperature, and a desiredtemperature. The control signal is used by energy circuits 200 to adjustthe energy output in an appropriate amount in order to maintain thedesired temperature delivered at the respective sensor. A multiplexercan be included to measure current, voltage and temperature, at numeroussensors, and energy can be delivered to the energy delivery device 189in monopolar or bipolar fashion.

Controller 198 can be a digital or analog controller, or a computer withsoftware. When controller 198 is a computer it can include a CPU coupledthrough a system bus. On this system can be a keyboard, a disk drive, orother non-volatile memory systems, a display, and other peripherals, asare known in the art. Also coupled to the bus is a program memory and adata memory.

User interface and display 196 includes operator controls and a display.Controller 198 can be coupled to imaging systems, including but notlimited to ultrasound, CT scanners, X-ray, MRI, mammographic X-ray andthe like. Further, direct visualization and tactile imaging can beutilized.

The output of current sensor 190 and voltage sensor 192 is used bycontroller 198 to maintain a selected energy level at energy deliverydevice 189. The amount of energy delivered controls the amount ofenergy. A profile of energy delivered can be incorporated in controller198, and a preset amount of energy to be delivered can also be profiled.

Circuitry, software and feedback to controller 198 result in processcontrol, and the maintenance of the selected energy that is independentof changes in voltage or current, and are used to change, (i) theselected energy, (ii) the duty cycle (on-off and wattage), (iii) bipolaror monopolar energy delivery, and (iv) infusion medium delivery,including flow rate and pressure. These process variables are controlledand varied, while maintaining the desired delivery of energy independentof changes in voltage or current, based on temperatures monitored atsensors 191.

Current sensor 190 and voltage sensor 192 are connected to the input ofan analog amplifier 204. Analog amplifier 204 can be a conventionaldifferential amplifier circuit for use with temperature sensors 191. Theoutput of analog amplifier 204 is sequentially connected by an analogmultiplexer 206 to the input of A/D converter 208. The output of analogamplifier 204 is a voltage which represents the respective sensedtemperatures. Digitized amplifier output voltages are supplied by A/Dconverter 208 to microprocessor 188. Microprocessor 188 may be a type68HCII available from Motorola. However, it will be appreciated that anysuitable microprocessor or general purpose digital or analog computercan be used to calculate impedance or temperature.

Microprocessor 188 sequentially receives and stores digitalrepresentations of impedance and temperature. Each digital valuereceived by microprocessor 188 corresponds to different temperatures andimpedances.

Calculated energy and impedance values can be indicated on userinterface and display 196. Alternatively, or in addition to thenumerical indication of energy or impedance, calculated impedance andenergy values can be compared by microprocessor 188 with energy andimpedance limits. When the values exceed predetermined energy orimpedance values, a warning can be given on user interface and display196, and additionally, the delivery of RF energy can be reduced,modified or interrupted. A control signal from microprocessor 188 canmodify the energy level supplied by energy source 203

FIG. 10 illustrates a block diagram of a temperature/impedance feedbacksystem that can be used to control cooling medium flow rate through thecatheter into the expandable member. Ablative energy is delivered toenergy delivery device 189 by energy source 203, and applied to tissue.A monitor 210 ascertains tissue impedance, based on the energy deliveredto tissue, and compares the measured impedance value to a set value. Ifthe measured impedance exceeds the set value a disabling signal 211 istransmitted to energy source 203, ceasing further delivery of energy tothe energy delivery device 189. If measured impedance is withinacceptable limits, energy continues to be applied to the tissue. Duringthe application of energy to tissue sensor 191 measures the temperatureof tissue and/or energy delivery device 189. A comparator 214 receives asignal representative of the measured temperature and compares thisvalue to a pre-set signal representative of the desired temperature.Comparator 214 sends a signal to a flow regulator 216 representing aneed for a higher cooling medium flow rate, if the tissue temperature istoo high, or to maintain the flow rate if the temperature has notexceeded the desired temperature.

While the present invention is disclosed by reference to the preferredembodiments and examples detailed above, it is to be understood thatthese examples are intended in an illustrative rather than limitingsense, as it is contemplated that modifications will readily occur tothose skilled in the art, which modifications will be within the spiritof the invention and the scope of the appended claims.

I claim:
 1. An apparatus for ablating at least a portion of a nasalconcha comprising:an introducer having a distal portion with a lengthoperable for positioning the introducer distal portion through a nostrilof a patient into a nasal meatus adjacent a surface of a nasal concha,the introducer including a longitudinal axis and a side port formed in aside wall of the introducer; an energy delivery means coupled to theintroducer distal portion for delivering sufficient ablative energy tothe nasal concha to create an interior ablation section of the nasalconcha; and a nasal concha ablation protection means coupled to theenergy delivery means the nasal concha ablation protection means havinga large enough protection surface positionable adjacent to an exteriorsurface of the nasal concha to minimize an ablation of the exteriorsurface of the nasal concha when energy is delivered to the interiorablation section.
 2. The apparatus according to claim 1 wherein theapparatus further includes an insulating means for preventing thedelivery of ablative energy to a selected tissue section forming aportion of the nasal meatus.
 3. The apparatus according to claim 1wherein the nasal concha ablation protection means includes aninsulating means for preventing the delivery of ablative energy to aselected area of the nasal concha.
 4. The apparatus according to claim 1wherein the energy delivery means delivers electromagnetic energy. 5.The apparatus according to claim 1 wherein the energy delivery meansdelivers energy selected from the group consisting of RF, microwave,ultrasound, pulsed laser, and diffused laser energy.
 6. The apparatusaccording to claim 1 wherein the energy delivery means delivers RFradiation with a frequency between about 300 megahertz and about 700megahertz.
 7. The apparatus according to claim 1 wherein the energydelivery means delivers sufficient RF radiation to deliver between about5 and about 30 watts of energy to the portion of the nasal concha beingablated.
 8. The apparatus according to claim 1 wherein the energydelivery means delivers ablative energy through the surface of the nasalconcha into an interior section of the nasal concha.
 9. The apparatusaccording to claim 1 wherein the energy delivery means delivers ablativeenergy through the surface of the nasal concha into an interior sectionof the nasal concha substantially bloodlessly.
 10. The apparatusaccording to claim 1 wherein the energy delivery means delivers ablativeenergy through the surface of the nasal concha into an interior sectionof the nasal concha without the formation of an external wound on thesurface of the nasal concha.
 11. The apparatus according to claim 1wherein the nasal concha ablation protection means includes a coolingmeans for cooling at least a portion of the exterior surface of thenasal concha during the delivery of ablative energy.
 12. The apparatusaccording to claim 1 wherein the nasal concha ablation protection meansincludes an expandable member which conforms to the surface of the nasalconcha when expanded.
 13. An apparatus for ablating an interior portionof a nasal concha without ablating tissue forming a surface of the nasalconcha comprising:an introducer having a distal portion with a lengthoperable for positioning and maneuvering the introducer distal portionthrough a nostril of a patient into a nasal meatus adjacent a surface ofa nasal concha; an energy delivery means at the introducer distalportion for delivering sufficient ablative energy to create an internalablation section of the nasal concha; and a nasal concha ablationprotection means coupled to the energy delivery means, the nasal conchaablation protection means having a large enough protection surfacepositionable adjacent to an exterior surface of the nasal concha tominimize an ablation of the exterior surface of the nasal concha whenenergy is delivered to the interior ablation section.
 14. The apparatusaccording to claim 13 wherein the energy delivery means deliversablative energy to the internal section of the nasal concha withoutpenetrating the surface of the nasal concha with an element of theapparatus.
 15. The apparatus according to claim 13 wherein the energydelivery means delivers ablative energy to the internal section of thenasal concha without the formation of a wound on the surface of thenasal concha.
 16. The apparatus according to claim 13 wherein the nasalconcha ablation protection means includes a cooling means for cooling atleast a portion of the exterior surface of the nasal concha during thedelivery of ablative energy.
 17. The apparatus according to claim 16wherein the cooling means is adapted to receive a cool medium from amedium source to cool the surface of the nasal concha.
 18. The apparatusaccording to claim 13 wherein the nasal concha ablation protection meansincludes an expandable member which conforms to the surface of the nasalconcha when expanded.
 19. The apparatus according to claim 18 whereinthe apparatus further includes a cooling means coupled to the expandablemember for cooling the surface of the nasal concha during the deliveryof ablative energy.
 20. The apparatus according to claim 19 wherein thecooling means receives a cool medium from a medium source to cool thesurface of the nasal concha.
 21. The apparatus according to claim 13wherein the apparatus includes an insulating means coupled to the energydelivery means for preventing the delivery of ablative energy to aselected tissue area forming a portion of the nasal meatus.
 22. Theapparatus according to claim 13 wherein the energy delivery meansdelivers electromagnetic energy.
 23. The apparatus according to claim 13wherein the energy delivery means delivers energy selected from thegroup consisting of RF, microwave, and ultrasound energy.
 24. Theapparatus according to claim 13 wherein the energy delivery meansdelivers RF radiation.
 25. The apparatus according to claim 24 whereinthe energy delivery means delivers RF radiation with a frequency betweenabout 300 megahertz and about 700 megahertz.
 26. The apparatus accordingto claim 13, wherein the introducer distal portion further includes atleast one sensor for measuring a property selected from the groupconsisting of an amount of energy delivered by the energy deliverydevice, an amount of heat generated at a location, an amount ofimpedance generated, and a temperature at a location.
 27. The apparatusaccording to claim 26, wherein the energy delivered to the energydelivery device is controlled by a processor in response to a propertymeasured by the sensor.